16 DR. P. P. CARPENTER ON THE SHELLS OF PANAMA. 



251. Rissoa, sp. md. This is a broken specimen of Chemnitzia 

 turrita, P. 230. 



252. ? Cingula inconspicua. This unfortunate name, liable to be 

 confounded with Rissoa inconspicua, Alder, and IRissoa inconspicua, 

 C. B. Ad., will not be needed, as the type belongs to another sub- 

 order, and = Chrysallida ovulum, M. 512. The Professor did not 

 observe its close relationship with his Chemnitzia communis. 



253. Cingula paupercula, C. B. Ad. A good species. 



254. ? Cingula terebellum Parthenia exarata, M. 501. Although 

 I took every pains, in preparing the Maz. Cat., to identify Prof. 

 Adams's species, I was not prepared, in the writings of so careful a 

 naturalist who had devoted special attention to the minute species, 

 to find a Pyramidellid under Trochidae, especially with the mark 

 " apex subacute." The finding of a more perfect Mazatlan specimen 

 enables me to add to the diagnosis: "vertice nucleoso parvo, satis 

 extante, decliviter sito; interstitiis carinarum transversim rugulosis; 

 labro solidiore. Long. '087, long. spir. '057, lat. '038." 



255. ? Cingula turrita ( + P. 249, Rissoa notabilis) Parthenia 

 quinquecincta, M. 498. When a shell is described under two genera 

 in the same sheet, the advocates of unbending priority will find it 

 difficult to decide. As each name belongs to a widely removed 

 family, that last given is at least the most correct and distinctive. 



256. ILitiopa saxicola. The Professor states that this "shell 

 has the appearance of a Litiopa ;" but it wants both the peculiar 

 nucleus and the semitruncated columella ; also that the " labium 

 has a distinct deposit," of which I could not see any trace in either 

 of the specimens. It is probably a Cingula. 



257. 1 Adeorbis abjecta. This is the adult form of the shell, of 

 which P. 233, Littorina atrata, is the young. The striae are seen on 

 the lower as well as the "upper part of the whorls." The umbili- 

 cus, though "small" for an Adeorbis, is rather large for a Fossarus, 

 to which genus the species undpubtedly belongs. 



258. Vitrinella concinna. I could not find the "more or less 

 distinct ridge between the first two keels." 



259. Vitrinella exigua=M. 305. The omissions in the Pro- 

 fessor's diagnoses of this and other species, being supplied in the 

 Maz. Cat., need not be repeated here: v. M. pp. 236-247. 



260. Vitrinella janus. The Professor does not mention the fifth 

 keel, which bounds the umbilicus, and within which are the " minute 

 spiral striae." The "transverse striae" are strong between keels 

 2, 3, and 4 ; faint between 4 and 5, and between 1 and 2 ; and eva- 

 nescent near the suture. 



261 . Vitrinella minuta. The original type of this species accords 

 better with Ethalia than with Teinostoma, to which I had referred 

 the Cumingian type. 



262. Vitrinella modesta. The " modesty " of this unique shell is 



190 



